Pneumatic tire.



I UNIT D ST TES PATENT orrIoE.

WILLIAM EDGAR MUIITZ, OF LONDON, ENGLAND.

PNEUMATIC TIRE.

1,110,640. No Drawing.

To all whom it may concern Be it known that I, l VILLIAM EDGAR MUNTZ,

a subject of the King of Great Britain, and resident of the RoyalAutomobile Club, 89

" are Composed of vulcanizedrubber and a liningor reinforcement offabric of fibrous material.

It is found in practice that tires as at pres ent manufactured are farfrom durable and the lining material is liable to give way aftercomparatively little wear.

I have traced the weakness-of the material I to influence on the fiberemployed of the vulcanizing operation which has a tendency to weaken thefiber and to the great heat generated in runningat a high rate of speedwhich also has a damaging effect on the linstrength and durability ofexisting tires.-

Such a substance, is silk in its natural state which is very strong andelastic, of long fiber and easily Woven into a fabric suitable forembedding in rubber or for lining the-same in the manufacture of tires.

Hitherto the fabric or cord of pneumatic outer covers has been made ofcotton or other cellulose-fiber, generally of the finest Sea Island orEgyptian cotton, selected for its good quality and strength. Silk initsordinary manufactured state after it has been treated to removethe" umwhich it naturally contains may have een tried excould not besuccessfully perimentally but it used being too brittle and notsufficiently strong. j According to my present invention I use silk initsnatural state without its gum being Specification of Letters Patent.Patented Sept, 15, 1914. Application filed December 23, 1912. Serial No.788,357.

removed. It is then extremely stnnig and not brittle and the operationsusual in pre- Jaring raw silk for the market not having een performedthe c'ost of the article is to that extent reduced. Silk from the wildsilk worm, which has, I believe, only recently been capable ofmanufacture is very suitable for my purpose. A fabric woven from vthespun thread of the silk worm without the treating and dressing usual toremove the gum and make the material suitable for the -market hasthreetimes the strength of a cotton fabric of the same weight.

The advantage in elasticity implies also great advantages in resiliencyand for heavy vehicles where twin tires 'are now employed to getsufficient supporting power without destroying resiliency altogether, aswould be the casewith a single cotton made tire of suflicient strength,a single silk tire made according to my invention will fulfill everyrequirement. Reference has already been made to the liability whichthere is for the cotton in tires to become decomposed by the chemicalaction and heat set up in vulcanization and in running. All cellulose isdecomposed especially when in a confined space,

and loses its strength at about 212 F. or even less, whereas silk isunaffected under 400F. As a matter of actual experiment a single yarn ofthe present Sea Island fabric has a breaking strain of 18lbs. whichafter an exposure of (30 minutes to a temperature equivalent to 40 lbs.steam pressure diminishes to 13 lbs., whereas a silk yarn of the samebulk underwent no deterioration in strength whatever on being exposed toa temperature of 300 F. The heat developed in running, frequently longcontinued, is often high, also during vulcanization'where a steampressureiof say 40 lbs is-empl0yed,-

it is about 280 F. The temperature and All silks, as above mentioned,are treated and dressed to improve their appearance for theinarket,which operations, however, are

destructive to the qualities which render silk desirable for use in themanufacture of pneumatlc tires.

' W'hai; I claim and desire to-sectire by Letname to speclficatlon inthe presence 6f ters Patent of the United @tates 5' f b two subscribingwitnesses.

-A wheel tire 'havin a oundation a ric consisting of natural ilkincorporated with; WILLIAM EDGAR MUNTZ' 5 india rubber of usualformation, substan- Witnesses-z e I tially as described. 1, P. A.NEWTON,

In testimony whereof I have signed my H ALFRED S. BISHOP.

